新型气动雾化喷嘴喷雾特性的实验研究

对一种新型气动雾化喷嘴的喷雾特性进行了实验研究。该喷嘴的喷雾是由环缝射流和中心旋转射流剪切破碎中心燃油射流而形成。实验用二维激光测速测粒仪对喷嘴下游几个截面上气流和液滴的平均速度和脉动速度,以及液滴的粒度和浓度沿径向的分布进行了测量。研究了中心旋流强度对喷雾的影响。测量结果显示喷雾中心存在低速区和固体涡核,而喷雾边缘具有较高的速度。浓度呈空心分布。喷雾具有很大的湍流脉动。 

SPRAY CHARACTERISTICS OF A NEW AIR-ASSISTED ATOMIZER

The spray characteristics of a new air-assisted atomizer was investigated experimentally.Annular and central swirling air jets smash the fuel jet and make it spray.The radial distributions of the mean and fluctuating velocities of the air flow and drops,the drop size and the concentration were measured at several axial stations with 2D PDA.Two atomizers with different mixing chamber were tested to investigate the effect of the central swirling air jet on the spray structure.The radial distributions of the mean velocity show that a lower axial velocity region and a solid rotation body exist at the center of the spray.The radial profile of drop volume flux peaks drifts off the centerline,indicating a hollow cone spray.The results show that high turbulence occurs at the central region and the region where the central swirling jet intersects the annular jet.The radial position of maximum mean axial velocity moves outwards with increasing strength of swirling.The atomization performance of the atomizer with lower swirling strength is better than that of the atomizer with higher swirling strength near the atomizer exit,but downstream the both atomizers possess same atomization performance.